Ras R’Mel and Sidi Ali tunnels (Morocco)

The Ras R’Mel and Sidi Ali tunnels are single-track railway tunnels located on the Tangiers-Ras R’Mel railway line.
The tunnels excavation area is 8 m x 6 m. The soil thickness above the tunnel arch is 10 to 150 m.
The encountered soils are mainly sandstone-pelitic and clay-pelitic facies, with embedded sandstone banks.

The tunnels design was carried out with the finite element calculation software CESAR, using convergence confinement approach, for two different excavation methods (full cross-section and half cross-section). This allowed comparing loads and displacements for both methods.

Modelling and optimisation

The 2D finite element modelling allowed, as expected by the client and owner, to optimise the tunnel support and lining:

  • Optimisation of the tunnel support: calculation of the  maximum spacing between steel arches.
  • Optimisation of the lining in non-reinforced concrete.

Terrasol’s achievements:

The TEC contractor entrusted the group Setec TPI – Terrasol – Maroc Setec with the detailed design of:

  • Support
  • Lining
  • Portals
Characteristics
PERIOD :  2006-2007
Owner : ONCF
Project Manager : ONCF
Contractors : Chinese compagny (TEC)
Detailed design:
SETEC TPI
MAROC SETEC
TERRASOL
Main specifications :  

  • Tunnels length: 2600m (Ras R’Mel) et 600m (Sidi Ali)
  • Spacing between sidewalls: 4.50m
  • Excavated section: 50m²

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